斜桥动力特性

Vibrating characteristics of skew bridge

为了解斜桥振动频率的变化规律和冲击系数的合理取值,建立了等截面斜桥振动频率的超越方程和斜桥静、动力分析的有限元列式,用解析法和有限元法分析了斜度、支承方式、弯扭刚度比等结构参数对单跨斜桥结构前5阶振动频率的影响,对一座20 m跨空心板不同斜度的振动频率进行了现场测试和理论分析,最后对单跨斜桥车-桥系统的振动进行了研究,考察了车速、斜度对结构动挠度、动弯矩的影响。计算结果表明:斜度、支承方式对斜桥动力特性有重要影响,车辆的冲击效应与车速没有单调变化规律,挠度和弯矩的冲击系数不同。

To explore the change rules of vibrating frequencies and gain the rational impact factors of skew bridge,the transcendent equation of vibrating frequency and the finite element formulations of static and dynamic force analysis were derived.The influences of obliquity,supporting manner and the ratio of flexural stiffness to torsion stiffness on the first five order frequencies of single span skew bridge were studied.The vibrating frequencies under different obliquities for a 20 m-length void slab were tested and analyzed. The interaetion of vehicle-bridge system for single span skew bridge was studied, and the influences of vehicle velocity and obliquity on the dynamic deflection and dynamic moment were investigated. Calculational result indicates that for skew bridge, obliquity and supporting manner have important influences on dynamical characteristics, the impact effect of vehicle has no harmonious changing rule with vehicle velocity, and the impact factors of deflection and moment are different. 18 figs, 15 refs.